Comparative assessment of the solvation properties of dialkyldithiophosphates and dialkylmonothiophosphates of copper(I) in various processes

The article describes synthesized copper(I) dibutyldithiophosphate and dibutylmonothiophosphate, which are often formed as secondary products during flotation with sulfhydryl reagents. Their solvation properties were studied in various heterogeneous processes. A significant increase in the extraction of lithium chloride by tributyl phosphate was established in the presence of these reagents, especially noticeable for copper(I) dibutylmonothiophosphate. The increase in extraction recovery was due to the acceptor activity of the studied reagents driven by the copper(I) cation, which was prone to the formation of complex compounds with halide ions. The weaker effect of copper(I) dibutyldithiophosphate was associated with significant self-association of the product and a partial formation of low-active cyclic tetramers in the organic phase. The reagents were shown to be well absorbed from the solutions in toluene on nickel and copper(I) sulfides. The adsorption isotherms of the reagents reach saturation in the concentration range up to 0.0002 mol/l. The activity of copper dibutyldithiophosphate on nickel sulfide was also reduced in comparison with dibutylmonothiophosphate; however, this effect was less pronounced than in the extraction system. The differences in the adsorption properties of the studied reagents practically disappeared with copper(I) sulfide, which was probably caused by the additional coordination bond of sulfide copper with sulfur (=S) of the copper(I) dibutyldithiophosphate molecule. The obtained data show that the studied reagents may be more active collectors in flotation enrichment of ores than dibutylthiophosphoric acids or their sodium and potassium salts. This was primarily due to coordinatively unsaturated copper(I) cations in the molecules of the reagents, which provided the fixation of the reagents on the surface of sulfide minerals and their hydrophobization.